Effectiveness of EDTA and Modified Salt Solution to Detach and Kill Cells from Enterococcus faecalis Biofilm

• Published in: Journal of endodontics Vol. 42; no. 2; pp. 320 - 323
• Main Authors: de Almeida, Josiane, DDS, MSc, Hoogenkamp, Michel, Ing, Felippe, Wilson T., DDS, MSc, PhD, Crielaard, Wim, PhD, van der Waal, Suzette V., DDS, PhD
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-02-2016
• Subjects: Anti-Infective Agents - pharmacology; Biofilm detachment; biofilm disruption; Biofilms - drug effects; Dental Pulp Cavity - microbiology; Dentistry; disinfection; Edetic Acid - pharmacology; EDTA; Endocrinology & Metabolism; Enterococcus faecalis; Enterococcus faecalis - drug effects; Enterococcus faecalis - physiology; Microbial Viability - drug effects; modified salt solution; propidium monoazide; quantitative polymerase chain reaction; Real-Time Polymerase Chain Reaction; Root Canal Irrigants - pharmacology; Sodium Chloride - pharmacology; Sorbic Acid - pharmacology; Enterococcus faecalis; modified salt solution; disinfection; propidium monoazide; Biofilm detachment; biofilm disruption; quantitative polymerase chain reaction; EDTA
• ISSN: 0099-2399; 1878-3554
• DOI: 10.1016/j.joen.2015.11.017

Abstract Introduction Disruption of the matrix of endodontic biofilms will aid in their removal from a root canal. Therefore, the aim of this study was to investigate the efficacy of EDTA and a modified salt solution (MSS) to detach bacteria from biofilms. Methods Forty-eight-hour-old Enterococcus faecalis biofilms were grown on glass coverslips and then treated for 1 hour by immersion in 17% EDTA or MSS. Phosphate-buffered saline served as a negative control. Then, residual biofilm cells on the substrate and the detached cells in the supernatant were collected. Viability was verified by the colony-forming unit (CFU) counting method. Propidium monoazide (PMA) treatment in conjunction with quantitative polymerase chain reaction (qPCR) was also performed to detect the presence of E. faecalis 16S ribonucleic RNA genes. Data were analyzed using 1-way analysis of variance and Tukey or Kruskal-Wallis and Dunn tests. The Pearson R test evaluated the correlation between results from CFU and PMA (α = 5%). Results qPCR showed that EDTA detached 99% of biofilm cells, and MSS detached 94% of biofilm cells (both P  < .001). In contrast to EDTA, MSS was highly antimicrobial. The treatment promoted an ample log 7 reduction of the attached cells ( P  < .001), and almost no live cells were detected in the supernatant ( P  < .001). Positive correlations between CFU and qPCR with PMA were observed ( r  = 0.959 and r  = 0.729). Conclusions EDTA detached cells in biofilms with a minor antimicrobial effect. Besides a great antimicrobial effect, MSS also detached biofilm cells. These dispersals of biofilms give insights into new endodontic biofilm removal strategies.